One Piece: sign-in to Ryujin Jakka

West Blue, Seawing Island.

A brutal battle over the fabled Ope Ope no Mi—the coveted "Ultimate Devil Fruit"—was raging under heavy snowfall.

Meanwhile, on the snowy white plains, Donquixote Doflamingo toyed with the heart-shaped strawberry-like fruit in his hand, laughter echoing through the cold air.

"Corazon... tell me where Law is," Doflamingo sneered. "Or else..."

He pointed a single finger toward the sky.

Zing.

In an instant, countless razor-sharp white strings sprang from his body, weaving into the sky and looming over the island. Strings rained down, forming a deadly white field—the legendary Birdcage—descended over the entire island.

Whomever the threads touched, lost control of their bodies, turning their weapons and fists against one another in a brutal, bloody massacre. Some lucky unsnared ones tried to escape but were sliced into ribbons by the merciless strings.

In mere minutes, Seawing Island had become a frozen hell, dying the snow red with blood.

With a front row seat to the carnage before him, Corazon's pupil shrank n horror.

Standing amidst the blood-soaked scene, Donquixote Doflamingo smiled cruelly.

"All of this, you see... is because you refuse to cooperate, Corazon."

Corazon—Donquixote Rosinante—lay on the ground, blood staining the snow around him. Bullets riddled his body, and yet, he clung to life with sheer willpower.

His chest heaved with heavy breaths as he stared at the chaos around him.

"Is there truly... no other way?"

Despair gnawed at his heart. As an undercover agent of the Navy, Corazon knew better than anyone how ruthless Doflamingo could be. Even if he gave up Law's location, Doflamingo would never let anyone go.

However, the justice cultivated in his heart burned fiercely,

'Can I even change anything?' 

Corazon collapsed powerlessly, clinging on to the remnants of his willpower-but what good could that do? Would it change the reality before him?

Yet before the darkness could fully consume him—

Suddenly, a massive pillar of fire roared into the sky from the western side of the island.

The snow blizzard stopped.

The winds died.

It was as if the world itself held its breath in that very moment.

"What is that?!!"

Doflamingo's expression twisted in alarm. He sensed a terrifying pressure heading his way. Without hesitation, he unleashed a torrent of his Conqueror's Haki to defend himself, his instincts screaming of an incoming threat.

But it proved useless.

BOOM!

The Birdcage, said to be indestructible, was torn apart like paper before the might of the blazing inferno.

The inferno bloomed into a shower of divine flames, cascading down from the heavens, engulfing Seawing Island in its rain of fire. The thick snow melted instantly, revealing the hidden view beneath the snow-covered ground.

Doflamingo clutched the Ope Ope no Mi tighter, only to watch helplessly as a surge of flame swept it from his grasp.

"Damn it! My fruit!" he roared. His body was trembling, and the veins on his forehead were bulging.

What monster had launched such terrifying attacks?!

"Damn it!"

His victory had seemed certain, but now, not only had the fruit been snatched right in front of him, but the Birdcage was destroyed too. 

In the face of this unknown, overwhelming force—and with Vice Admiral Tsuru and the Navy fast approaching—Doflamingo had no choice but to grit his teeth and give his crew the order:

"Retreat!"

Meanwhile, aboard the approaching Navy fleet, Tsuru's eyes narrowed as she witnessed the unnatural flames engulfing Seawing Island.

"Change of plans. We land immediately. Stay sharp—it's more than just Doflamingo here."

She could feel it: the appearance of a new, unknown force could affect the retrieval of the Ope Ope no Mi. The importance of the fruit could not be overstated.

In a hidden corner on the island, away from the blaze, Roman, newly transmigrated into the One Piece world, sheathed his Ryūjin Jakka sword and caught the heart-shaped Ope Ope no Mi as it gently floated down from the air, cradled by the dying embers.

A faint smile hung on his lips.

"So this is the reward for signing in, huh? Pretty strong."

The mechanical voice of the system rang in his mind:

[Ding! . Welcome to the God-Tier Sign-In System!]

 [System guaranteed rewards - Signing in at Seawing Island: Obtained Ryūjin Jakka—the strongest and oldest fire-type Zanpakutō. Reiatsu - Spiritual pressure equivalent to Conqueror's Haki is included.]

[Ding! - Sign in at iconic locations in the original story to receive extra rewards. Must remain within a specified range to complete the sign-in!]

Hearing the system's timely notification, Roman's anticipation only grew.

Before he could linger more on his new prize, a small figure approached.

An avid One Piece fan like him instantly recognized him, it was Trafalgar Law—future member of the Seven Warlords of the Sea—staring wide-eyed at Roman. Under Corazon's desperate struggle, Law managed to escape Doflamigo's pursuit.

Thus, the young boy had seen everything: the Birdcage torn apart, the flames consuming the island.

If anyone could save Corazon... it was this man, possessing unfathomable strength.

Biting his lip, Law gathered his courage.

"N-Nii-san…Please...!" Law's voice trembled. "Please save Corazon! He's a good man... the most important person to me!" His voice wavered at first, but perhaps thinking of Corazon's sacrifice, he gathered his courage and yelled.

Roman walked past him without so much of a glance or a word.

Desperate and unwilling to give up, Law chased after him, tears welling in his eyes.

"I'll do anything! Give you anything! Please, help me save him! I can't lose him!"

Suddenly, Roman tossed something over his shoulder.

Thunk.

The Ope Ope no Mi bounced off Law's forehead and landed in the snow before him.

Stunned, Law picked up the fruit, cradling it in his trembling hands. His teary eyes widened in disbelief.

Long gone in the distance, Roman's calm voice carried by the wind reached Law's ears.

"Use your strength... to save the one most precious to you."

In response, Law wiped his tears away, clutching the Ope Ope no Mi to his chest.

In that moment, he made a silent vow.

No matter what it takes... in this life, I will follow him.

Because without this man, he would have lost everything.

Corazon sparked Law's hope to live with the Operation fruit and now, Law would use the fruit to burst forth a miracle and save Corazon.

On that day, Seawing Island bore witness to a new legend.

And Roman, like a passing flame, vanished from the island... as if he had never been there.